1. Field of the Invention
The present invention relates to an improved method and fabric container for controlling root growth, and more particularly, to an improved method and fabric container for controlling root growth of nursery stock planted in the ground prior to transplanting such nursery stock.
b. 2. Description of the Prior Art
The growing of nursery stock, such as trees and the like, in above-ground containers has been a commercial practice for many years. However, the practice of growing trees in such containers is efficient and economical only during the early period of development of the tree. The continued growth of trees in such containers involves a number of problems, e.g., high summer temperatures reduce the plant and root growth because the soil in the container reaches abnormally high temperatures. Low winter temperatures often damage or kill the roots of trees in containers, and the trees and containers are readily blown over. In contrast, when nursery stock such as trees are grown in the ground, the surrounding soil insulates the roots from high summer and low winter temperatures while maintaining the trees in an upright position without staking. However, once nursery stock is grown in the ground without confining its root growth, the root growth must be dug out of the ground resulting in a number of the roots being cut, and often, the death or dissatisfactory growth of the nursery stock after transplantation.
A method of growing nursery stock in the ground prior to transplanting such nursery stock wherein the root growth is confined in a porous fabric container is disclosed in U.S. Pat. No. 4,574,522 dated Mar. 11, 1986. In accordance with that method, nursery stock, e.g., a tree, is confined within a porous fabric container and planted in the ground within the container prior to transplantation. The porous fabric container has sufficient strength to constrict roots which penetrate it whereby the root growth outside the container is restricted and enlarged root nodule formation and root branching take place within the container. Upon transplanting the nursery stock, the container and nursery stock are unitarily removed from the ground and the restricted root growth outside the container readily breaks off or comes out of the ground. When transplanted, the container is removed and the root growth, nearly 100% complete, is placed in the ground. Because of the nodule formation and root branching which took place in the container, the root growth rapidly expands whereby the plant is very quickly nourished and anchored in the ground.
The particular fabric used in accordance with the method of U.S. Pat. No. 4,574,522 to form the porous but root constricting, fabric container is a nonwoven, needled fabric formed of synthetic staple fibers. While such fabric and containers formed therefrom have functioned well in carrying out the method of U.S. Pat. No. 4,574,522, there is a need for a fabric having an improved uniformity of thickness and strength. Also, there is a need for a fabric having an improved ability to catch root tips and cause them to initially penetrate the fabric, rather than contacting the inside surface of the fabric and failing to penetrate whereby spiral root growth within the container results.
By the present invention an improved method and fabric container for controlling root growth of nursery stock planted in the ground prior to transplantation meeting the needs described above are provided.